docs: def is_timeseries_profile_ortho_depth(nc, variable):
      '''
      Returns true if the variable is a time-series profile with orthogonal depth
      only.
  
      :param netCDF4.Dataset nc: An open netCDF dataset
      :param str variable: name of the variable to check
      '''
      # x(i), y(i), z(z), t(i, j)
      # X(i, j, z)
      dims = nc.variables[variable].dimensions
      cmatrix = coordinate_dimension_matrix(nc)
  
      for req in ('x', 'y', 'z', 't'):
          if req not in cmatrix:
              return False
  
      if len(cmatrix['x']) != 1:
          return False
      if cmatrix['x'] != cmatrix['y']:
          return False
  
      z = get_z_variable(nc)
      if cmatrix['z'] != (z,):
          return False
  
      i = cmatrix['x'][0]
  
      if len(cmatrix['t']) != 2:
          return False
      if cmatrix['t'][0] != i:
          return False
  
      j = cmatrix['t'][1]
  
      if dims == (i, j, z):
          return True
      return False